Point of Sales (POS) terminal devices to be used as, for example, checkout machines in retail stores may include a customer-side display device configured to display information for a customer who is involved in transactions, as well as a display device configured to display information for an operator (store staff member).
After the POS terminal device is installed, the height of the customer-side display device may need to be adjusted to a position so as to secure the customer's visibility.
In this case, as a structure for adjusting the height of the customer-side display device, there is a structure in which the customer-side display device and a casing of the POS terminal device are coupled to each other through a pole, and a part or all of the pole is configured to be extensible and contractible (to be accommodated in the casing) (Patent Literature 1).